In general there are two types of tomato crops grown, those which are grown for canning, and those which are grown for the fresh market. Canning tomatoes have long been mechanically harvested, while fresh market tomatoes have only rarely been mechanically harvested.
The present invention originated due to some peculiarities in the way tomatoes are grown in some parts of Florida. After the method and apparatus had been found to operate successfully there, they were modified somewhat for application to other growing areas and found to give improved results in many instances.
The system used in some parts of Florida is unique, and to many people it will appear nearly as fantastic as a science fiction story. The tomatoes are grown, not in soil, but in rock which has been broken up, and the growing process has many other unusual aspects. The present inventors do not claim to have invented the novel features of growing tomatoes in this manner, but restrict their claims to the harvesting of the crop. Since the way in which the tomatoes are grown gives rise to several problems that affect harvesting; an explanation of that growing method will be helpful.
In the parts of Florida where this unique method is practiced, there are old coral beds lying only a few feet above sea level with very little, if any, soil on top of them. The coral beds are broken up to a depth of about one foot or more to form a generally flat field. The field is then provided with raised beds located six feet on center, each bed being separated from its adjacent beds by a furrow about one foot deep. The furrows and beds all lie along a north-south axis. At intervals, some beds are omitted and replaced by a wide strip to be left uncultivated and provided with wells drilled at suitable uncultivated and provided with wells drilled at suitable intervals. These wells may extend down about twenty feet with the water table very high in these locations, only about four feet below the surface, and they are made only large enough for insertion of suitable pumping conduits. These wells are used for watering the tomatoes.
The next step before planting is to fertilize the field by injecting fertilizing liquid or gas into the beds. Immediately thereafter, plastic strips are laid over each bed and are simultaneously perforated by a roller carrying a series of perforated spikes. Next, larger holes are burned through the plastic at regular intervals, and a plug containing one or more seeds is inserted in each hole. The field is then watered, the seeds germinate, and the plants come up.
Both before and after germination the beds are watered overhead by large rotating jets of water that are sprayed from a truck or other suitable conveyance which moves from south to north along a well strip, in the direction of the prevailing winds. The truck moves from well to well, drawing out water and spraying it over the field.
When the plant is about eight inches tall, workers remove the lower shoots, which they term "suckers", leaving only two opposite laterals near the top of each small plant. It has been found that this early treatment increases the amount of fruit relative to the amount of leaves on the plant and produces a much larger harvestable crop than would otherwise be obtained. As, the plant then continues to grow, it tends to sprawl due to its early treatment. During this second growth period, further fertilizer may be injected from time to time from the sides of the bed along the furrows.
When it comes time to harvest the tomato crop the ripe tomatoes may be pulled off by hand, but mechanical harvesting can save considerable tedious and expensive labor.
In the past, mechanical harvesting has been difficult, partly because the plants are so sprawled that it is difficult to sever the stems properly. The powered sickles long used to cut off tomato plants grown for canning, are unsatisfactory for they simply glide over a large proportion of the plants and fail to harvest the ones they glide over. As a result, many plants have tended to the trampled under the mechanical harvester and much of the crop lost. Other types of cutters gave no significant improvement. Moreover, the plastic sheet tended to catch in them and also to get in the way of harvesting. Harvesters that dug into the soil and brought up a thin layer of soil were worse than useless in the broken-rock fields.
The present invention relates largely to apparatus and method which can harvest such crops efficiently, by operating over the plastic and cutting and picking up every plant. The invention, summarized below and then described in detail, involves stretching the stem of the plant upwardly and then severing it easily, while substantially simultaneously picking up the severed portion and then depositing it on an upwardly moving pickup conveyor.
Once the apparatus and method of this invention had been perfected for use in those unusual Florida conditions, it was found to offer some advantages over more common types of tomato harvesting as practiced heretofore, so that it was decided to try it out in still other environments.
For fresh market tomatoes in areas where there is good soil and where the novel Florida method is not used, the apparatus and certain aspects of the method have been found to be valuable in two quite different types of harvesting systems. In one, the stems of the tomato plants are cut two or three hours before the plants are to be picked up. This method can also be used in the Florida system and elsewhere, if desired. This pre-cutting affects the tenacity of attachment of the fruit and also toughens the skins, so that upon later shaking the stems tend rather uniformly to break off right at the tomato rather than at a location an inch or two from the tomato. Stems broken at a point away from the tomato, leave stiff sharp portions attached to the fruit that tend to damage other adjacent tomatoes. Stems broken off right at the tomato, minimize amount of such damage. The two or three hour delay between cutting and shaking not only increases this desirable tendency but also tends to make the tomato skins somewhat more resistant to damage.
After the precutting, the present invention makes it easier to pick up the tomato vines mechanically and deposit them on the pickup conveyor as it moves through the field. The improvement is obtained by the invention's use of an overhead assist that helps lift the severed plants and drop them onto the conveyor.
The method and apparatus of this invention also have advantages when using the normal type of powered sickle in normal fields of tomatoes, to cut off the plant at the time that it is harvested. Since there is a lifting of the plant from above, both at the time of severance and shortly before and after it, much less dirt is taken up by the pickup, so that in fields where dirt tends to be a problem the tomatoes can be harvested much more cleanly than heretofore. Particularly for canning tomatoes this has a great advantage, since large bins or trailer loads of canning tomatoes have often been rejected, a whole bin or trailer load at a time, due to the presence of too much dirt. When the tomatoes are harvested according to the present invention, a maximum yield can be obtained while a minimum amount of dirt is picked up.
Thus, the invention has among its objects the solution of several significant problems. One object of the invention is to enable the improved mechanical harvesting of fresh market tomatoes.
Another object of the invention is to enable the mechanical harvesting of fresh market tomatoes grown in broken-rock fields in beds which have been covered by plastic sheets.
Another object is to obtain efficient severing and treating of tomato plants during the difficult harvesting conditions obtaining when tomatoes are grown in rock-fields with their roots under plastic.
Another object of the invention is to provide an overhead assist system which reduces the amount of dirt picked up in fields where there is dirt and thereby enables the harvesting of a maximum amount of clean tomatoes, whether they are canning tomatoes or fresh market tomatoes.
Another object of the invention is to provide for harvesting of fresh market tomatoes by a system in which the vines are pre-cut near ground level and are then lifted onto the tomato harvester, again with a minimum amount of dirt being picked up.
Other objects and advantages of the invention will appear from the following description of some preferred embodiments thereof.